The weighty problem of obesity continues to be misunderstood in Australian culture.

That's according to Associate Professor Wendy Brown, who's Director of Monash University's Centre of Obesity Research and Education.

She says there's a misperception that obesity is caused primarily by weakness of character. There's a stigma to being fat.

"Obese people are still the group in society that it's okay to pick on."

One in four adults in this country is obese, according to the Australian Bureau of Statistics.

The human body loves fat

"People make judgments about people who are obese," says Wendy Brown. "They assume that they're lazy, they assume that they eat poorly, they assume that they're somehow morally inept.

"In fact they're fighting biology. We've got Stone Age genes but we live in a modern society.

"From the body's point of view, putting on some weight is actually a good thing, because it thinks, 'Well, there could be a famine round the corner... '

So once you put on weight, your body fights you when you try to lose it.

At the same time, she says, the medical profession's key message on obesity is not being well enough communicated; that extra weight has a direct and significant impact on health.

Consider a person with a body mass index of greater than 40. That individual would have a three and a half or four times greater chance of dying compared to someone of the same age in the normal weight range.

Surgery up by 300 per cent

But clearly many people are heeding the warning.

Since 2005 there has been a 300 per cent increase in obesity surgery in Australia.

Brian Robson says the decision to curtail his weight through surgery was undoubtedly the correct one. He's had an operation known as a gastric sleeve, in which 80 per cent of the stomach is removed.

He says his obesity was to blame for a range of health problems, from diabetes to sleep apnea.

"The doctor said basically, "You're okay now, mate, but I don't like your chances in six years time."

After having a very active lifestyle in earlier years, with lots of sport, Robson stopped exercising but continuing eating in the same way.

"I tried everything but...the body was in a famine mode and no matter what I did to lose I just started putting it back on again."

One weapon in the arsenal

Surgery is an important weapon against obesity, but it's not for everyone.

"We just don't go and operate on everybody," says Wendy Brown. "Otherwise instead of 15000 we'd be doing 2.6 million operations a year.

"We only resort to surgery when people have really tried everything else...and we offer surgery only in the context of a diet and exercise program."

Brown is in Darwin to attend the Obesity Surgery Society's annual scientific meeting this week.

The society is setting up a trans-Tasman registry to track bariatric procedures over the long-term. The rapid growth in the sector has sparked a need to more closerly monitor outcomes.

"If you take the example of that French breast implant that has recently been found to be faulty-if there had been a register of those, we would've known who had the procedure...and we may have had an early warning."

"We want to be able to offer that to the people who chose to undergo obesity surgery."